Advances in electronic technology cause integrated circuits to be formed on substrates such as silicon wafers with ever increasing packing density of active components. The formation of circuits is carried out by sequential application, processing, and selective removal of various components from the substrate.
At times it is desirable to deliver steam to the semiconductor wafer treatment chamber as an aspect of the treatment process. U.S. Pat. No. 6,837,252 describes an apparatus for treating a workpiece with steam and ozone. The disclosure of this patent describes alternative configurations, whereby liquid is dispensed into the chamber, as shown in FIG. 4 of the patent, and steam is dispensed as shown in FIG. 5 of the patent. As described therein, steam is generated by a steam generator or boiler. See column 15, lines 37-56.
In US Patent Application Publication No. 2007/0161248, various methods for introducing water vapor into a treatment chamber by generating the vapor outside of the treatment chamber were described at paragraph [0047]. Specifically, the disclosure stated that “For instance, externally produced water vapor could be supplied to the chamber as a gas, or as component of a mixture of gasses. In one embodiment, vapor could be produced by bubbling a gas (eg. N2) through a column of water (preferably hot water). In another embodiment, the gas could pass over the surface of a quantity of water. In another embodiment, the gas could pass through an irrigated packed column as commonly used in chemical engineering. In another embodiment, substantially pure water vapor could be produced by boiling liquid water. The gaseous products from any of these alternatives could be further heated. Other embodiments are also possible.”
It would be desirable to identify alternative techniques and systems for treatment of semiconductor wafers using water vapor.